Effect Of Graphene And Mo-doping On Electrochemial Performance Of Lini_0.6Co_0.2Mn_0.2O₂ Material

The demand for energy in human society production and development is increasing,but the reserves of non-renewable energy such as fossil energy aredecreasing,so the study of new energy materials has a huge social andeconomic significance for human beings.Lithium-ion battery is an excellent energy storage device,it has the performance of high specific energy density and good cycle performance.Layered nickel-cobalt-manganese composite material has high theoretical capacity,good cycle stability and thermal stability,widely followed by researchers.This experiment using the Ni0.6Co0.2Mn0.2(OH)2 and Li2CO3 as the raw material to synthesis the LiNi0.6Co0.2Mn0.2O2 cathode material.Then,adding graphene and doping molybdenum element to improve its electrochemical performance.Tested the charge and discharge properties of the material1.Effect of molybdenum doping in NCM622 cathode material.Mixing the(NH4)6Mo7O2·4H2O and NCM622 cathode material with different ratio,then,high temperature sintering in an oxygen atmosphere to obtain different contents of molybdenum doped samples.The material with the molar percentage 0.5%shows high electrochemical performance.The initial discharge specific capacity of 0.1C rate is 210.9mAhg-1(higher than 177.8mAhg-1 of the sample without modified).The discharge capacity is 205.6mAhg-1 at 1C rate at the first cycle and 201.8mAhg-1 after 50 cycles,with the capacity retention of 98.2%.2.Effect of adding graphene in NCM622 cathode material.Using hydrothermal to reduction the graphene oxide,mixing the graphene,acetylene black and NCM622 cathode material with different ratio,tested the charge and discharge properties of the material.The material with the graphene mass percentage 1%shows high electrochemical performance.The initial discharge specific capacity of 0.1 C rate is 201.2mAhg-1.The discharge capacity is 182.5mAhg-1 at 1C rate at the first cycle and 180.5mAhg-1 after 50 cycles,with the capacity retention of 98.9%.The specific discharge capacity at 5C rate is about 158mAhg-1.3.Effect of adding graphene and molybdenum doping in NCM622 cathode material.Mixing the graphene and molybdenum doped NCM622 cathode material with different ratio,tested the charge and discharge properties and morphology of the material.The initial discharge specific capacity of 0.1 C rate is 195.1mAhg-1.The discharge capacity is 168.9mAhg-1 at 1C rate at the first cycle and 165.2mAhg-1 after 50 cycles,with the capacity retention of 96.2%.